Cook spaghetti or egg noodles according to package instructions until al dente. Drain and set aside.

In a large skillet over medium heat, melt butter. Add onions and garlic; sauté until fragrant (about 2 minutes). Add mushrooms and cook until tender.

Sprinkle flour over vegetables and stir well. Gradually whisk in chicken broth until smooth. Bring to a simmer; add heavy cream and Parmesan cheese until melted.

In a bowl, mix cooked pasta with shredded turkey. Pour sauce over mixture and stir until coated.

Transfer to a greased baking dish, sprinkle with more Parmesan, and bake at 350°F for 25-30 minutes until bubbly and golden.

Let sit for a few minutes before serving with fresh parsley garnish if desired.